Studies will be carried out on two separate projects: 1) The electrophysiological properties of pituitary cells will be studied in detail in order to determine the relation, if any, between action potential activity and hormone secretion. The results obtained will be compared with those obtained previously from pituitary tumor cells. 2) Spectral characteristics of inhibitory noise will be examined at synapses in the brainstem of the Lamprey. Noise produced by various putative transmitters will be campared with that produced by activation of inhibitory pathways to the same cells.